The research was undertaken in the entomological field of Bangladesh Agricultural University (BAU), Mymensingh during the Boro crop of 2015-16 and 2016-17. Fourteen generic of single-molecule insecticide along with control were used separately in this experiment. Among the 14 single-molecule insecticides, four generics were synthetic pyrethroid group insecticide. Causes of resurgence were determined in the form of a resurgence ratio. More resurgence of brown planthopper, Nilaparvata lugens (Stål) on rice was induced by the application of all synthetic pyrethroids i.e., Cypermethrin, Deltamethrin, Fenvalerate, and Lambda cyhalothrin along with Acetamiprid, Chlorpyrifos, Phenthoate, and Thiamethoxam (resurgence ration 1.0 or above) compared to Pymetrozine 50WG (0.26), Dinotefuran 20SG (0.29), Isoprocarb/MIPC 75WP (0.43), Cartap 50SP (0.76) and Imidacloprid 20SL (0.91). Commonly used recommended insecticides i.e., Imidacloprid 20SL, Cartap 50SP, Isoprocarb/MIPC 75WP, Pymetrozine 50WG, and Thiamethoxam 25WG were used in 3 different doses (i.e., low, recommended, and high) and found that all recommended insecticides were induced higher resurgence ratio (≥1.0) except Pymetrozine 50WG when applied at sub-lethal dose. A positive correlation was found between resurgence ratio and yield loss.
Keywords: Brown planthopper, insecticide, resurgence ratio, yield loss.